The overall objective of this proposal is to investigate the changes in the central nervous system of gonatropic secretion during sexual maturation of human beings. Specifically, we have proposed to evaluate the effects of sex steroids on gonadotropin-releasing hormone (GnRH) secretion and to test the hypothesis that endogenous opiates and alpha-adrenergic neurotransmitters become involved in the regulation of GnRH secretion during human sexual maturation.